Central receiver concentrating solar energy systems include a central receiver mounted atop a tower and a field of heliostats surrounding the tower. The heliostats reflect the sun's rays onto the central receiver, which generally heats a medium to produce superheated steam or other thermodynamic working fluid which then drives a generator set to generate electricity.
Each heliostat includes a reflector assembly, which is often in the form of one or more rectangular glass mirrors, movably mounted on a support structure. The support structure is typically a steel or concrete pillar which is secured to a foundation such as a concrete block cast in a foundational hole in the ground. The reflector assembly may include a tracking mechanism which is able to control movement of the reflector so that sunlight is accurately reflected onto the stationary central receiver as the relative position of the sun changes during the day.
The construction of central receiver concentrating solar energy systems may require a significant amount of earth work in preparing the foundations for the heliostat support structures. The heliostats are expensive to manufacture and install and generally constitute about 40-50% of the total cost of existing central receiver concentrating solar energy plants. Stability of the heliostat support structures is an important requirement, because the systems must operate in strong winds and other adverse weather conditions, which is why existing heliostats are generally mounted in secure individual foundations or in a lattice-type structure. An example of a lattice-type structure is the “Sierra Suntower” system made by eSolar®.
It would be advantageous to have a heliostat support structure which is easily installed, is sufficiently stable and efficient and which is relatively cost-effective.